User manual SELECTRONICS TDA7293

[. . . ] Different values can be used; the following table can help the designer. COMPONENTS R1 (*) R2 R3 (*) R4 SUGGESTED VALUE 22k 680 22k 22k PURPOSE INPUT RESISTANCE LARGER THAN SUGGESTED INCREASE INPUT IMPEDANCE SMALLER THAN SUGGESTED DECREASE INPUT IMPEDANCE CLOSED LOOP GAIN DECREASE OF GAIN INCREASE OF GAIN SET TO 30dB (**) INCREASE OF GAIN DECREASE OF GAIN ST-BY TIME CONSTANT MUTE TIME CONSTANT INPUT DC DECOUPLING FEEDBACK DC DECOUPLING MUTE TIME CONSTANT ST-BY TIME CONSTANT BOOTSTRAPPING LARGER MUTE ON/OFF TIME LARGER ST-BY ON/OFF TIME LARGER ST-BY ON/OFF TIME LARGER MUTE ON/OFF TIME SMALLER ST-BY ON/OFF TIME; POP NOISE SMALLER MUTE ON/OFF TIME HIGHER LOW FREQUENCY CUTOFF HIGHER LOW FREQUENCY CUTOFF SMALLER MUTE ON/OFF TIME SMALLER ST-BY ON/OFF TIME; POP NOISE SIGNAL DEGRADATION AT LOW FREQUENCY R5 C1 10k 0. 47µF C2 22µF C3 C4 10µF 10µF C5 22µFXN (***) C6, C8 C7, C9 1000µF 0. 1µF SUPPLY VOLTAGE BYPASS SUPPLY VOLTAGE BYPASS DANGER OF OSCILLATION (*) R1 = R3 for pop optimization (**) Closed Loop Gain has to be 26dB (***) Multiplay this value for the number of modular part connected Slave function: pin 4 (Ref to pin 8 -VS) -VS +3V MASTER -VS +1V UNDEFINED Note: If in the application, the speakers are connected via long wires, it is a good rule to add between the output and GND, a Boucherot Cell, in order to avoid dangerous spurious oscillations when the speakers terminal are shorted. The suggested Boucherot Resistor is 3. 9/2W and the capacitor is 1µF. -VS SLAVE D98AU821 5/15 TDA7293 INTRODUCTION In consumer electronics, an increasing demand has arisen for very high power monolithic audio amplifiers able to match, with a low cost, the performance obtained from the best discrete designs. The task of realizing this linear integrated circuit in conventional bipolar technology is made extremely difficult by the occurence of 2nd breakdown phoenomenon. It limits the safe operating area (SOA) of the power devices, and, as a consequence, the maximum attainable output power, especially in presence of highly reactive loads. [. . . ] Full protection against electrostatic discharges on every pin is included. Figure 5: Single Signal ST-BY/MUTE Control Circuit mute functions, independently driven by two CMOS logic compatible input pins. The circuits dedicated to the switching on and off of the amplifier have been carefully optimized to avoid any kind of uncontrolled audible transient at the output. The sequence that we recommend during the ON/OFF transients is shown by Figure 4. The application of figure 5 shows the possibility of using only one command for both st-by and mute functions. On both the pins, the maximum applicable range corresponds to the operating supply voltage. APPLICATION INFORMATION HIGH-EFFICIENCY Constraints of implementing high power solutions are the power dissipation and the size of the power supply. These are both due to the low efficiency of conventional AB class amplifier approaches. Here below (figure 6) is described a circuit proposal for a high efficiency amplifier which can be adopted for both HI-FI and CAR-RADIO applications. 7/15 MUTE MUTE/ ST-BY 10K 20K 30K STBY 1N4148 10µF 10µF D93AU014 3) Other Features The device is provided with both stand-by and TDA7293 The TDA7293 is a monolithic MOS power amplifier which can be operated at 100V supply voltage (120V with no signal applied) while delivering output currents up to ±6. 5 A. This allows the use of this device as a very high power amplifier (up to 180W as peak power with T. H. D. =10 % and Rl = 4 Ohm); the only drawback is the power dissipation, hardly manageable in the above power range. The typical junction-to-case thermal resistance of the TDA7293 is 1 oC/W (max= 1. 5 oC/W). To avoid that, in worst case conditions, the chip temperature exceedes 150 oC, the thermal resistance of the heatsink must be 0. 038 oC/W (@ max ambient temperature of 50 oC). As the above value is pratically unreachable; a high efficiency system is needed in those cases where the continuous RMS output power is higher than 50-60 W. The TDA7293 was designed to work also in higher efficiency way. For this reason there are four power supply pins: two intended for the signal part and two for the power part. T1 and T2 are two power transistors that only operate when the output power reaches a certain threshold (e. g. If the output power increases, these transistors are switched on during the portion of the signal where more output voltage swing is needed, thus "bootstrapping" the power supply pins (#13 and #15). The current generators formed by T4, T7, zener diodes Z1, Z2 and resistors R7, R8 define the minimum drop across the power MOS transistors of the TDA7293. L1, L2, L3 and the snubbers C9, R1 and C10, R2 stabilize the loops formed by the "bootstrap" circuits and the output stage of the TDA7293. By considering again a maximum average output power (music signal) of 20W, in case of the high efficiency application, the thermal resistance value needed from the heatsink is 2. 2 oC/W (Vs =±50 V and Rl= 8 Ohm). [. . . ] A B C E F G G1 H1 H2 L L1 L2 L3 L4 L5 L6 L7 S S1 Dia1 2. 65 1. 9 1. 9 3. 65 17. 25 10. 3 20. 57 18. 03 2. 54 17. 5 10. 7 5. 28 2. 38 2. 9 2. 6 2. 6 3. 85 0. 104 0. 075 0. 075 0. 144 17. 75 10. 9 0. 679 0. 406 0. 49 0. 66 1. 14 17. 57 19. 6 20. 2 0. 810 0. 710 0. 100 0. 689 0. 421 0. 208 0. 094 0. 114 0. 102 0. 102 0. 152 0. 699 0. 429 1. 27 17. 78 mm TYP. 5 2. 65 1. 6 0. 55 0. 75 1. 4 17. 91 0. 019 0. 026 0. 045 0. 692 0. 772 0. 795 0. 050 0. 700 MIN. 0. 197 0. 104 0. 063 0. 022 0. 030 0. 055 0. 705 OUTLINE AND MECHANICAL DATA Multiwatt15 H 14/15 TDA7293 Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. [. . . ]